A recent study has concluded that the addition of zircon increases the solar reflectance of ceramic roof tiles. 

A paper summarising the findings of the study was presented at the ECerS conference in Turin, Italy June 2019.

The paper reported if zircon-containing ceramic tiles are used as a building envelope, they improve the thermal comfort within the building by reducing energy requirements.

When compared to other existing solutions including paints and cool paints, it reduces maintenance costs due to the high resistance of ceramic tiles to wear, dirt and stains. 

Carried out both on a laboratory scale and by field trials, zircon was added to 36 tile samples both as an opacifier directly into the glaze formulation (up to 10 percent by weight), and as frit component (up to 6.6 percent by weight).

The solar reflective index (SRI) was then calculated on all samples. The colorimetric coordinates were also determined, to evaluate any colour variation due to the presence of zircon.

The results of tests found that, in general, the addition of zircon increases the solar reflectance index (SRI) of the glazes, the effect being more pronounced when zircon is added as an opacifier.

Also, as the zircon percentage in the glaze increases the SRI value increases linearly for all the colours analysed.

Monitoring of the surface temperatures of the tile samples when exposed outdoors to solar radiation confirms that the higher values of brightness and solar reflectance parameters of the glaze are associated entirely to the addition of zircon.       

“This study shows that by actively choosing zircon-containing tiles for the building envelope, architects and their customers can significantly reduce the overall environmental impact of the building, while lessening the roof maintenance required over time,” says Dr Keven Harlow, executive director of the Zircon Industry Association.